Typical prior art microbial fuel cells, such as the one depicted in FIG. 1A, used buried anode structures 10 to capture free electrons generated when bacteria metabolize sediment-based nutrients. An electrical circuit is formed when the captured electrons are passed thru an electrical load 20 (or battery) en route to sources of dissolved oxygen. Burying the anodes 10 yields a natural bifurcation of the anaerobic sediment 30 and oxygen rich seawater 40 and produces a voltage potential between the anodes 10 and cathodes 50. Any leakage or diffusion of oxygen towards the anodes 10 simply shorts out the electron flow and prevents the microbial fuel cell from operating.
Some prior art microbial fuel cell designs, such as the design shown in FIG. 1B, deploy the anodes 10 within a chamber 60 that creates an oxygen-free (anaerobic) condition about the anodes 10. This design eliminates the need for burying the anode structure 10 as the chamber 60 serves as a barrier against dissolved oxygen in the ambient seawater 40 provided there is an adequate seal with the sediment 30. A need exists for an improved microbial fuel cell.